On December 18, 2010, he was summoned to the Canadian Senate on the advice of Prime Minister Stephen Harper and sat as a Conservative. Following his appointment to the Senate, Smith announced his intention to seek the nomination to run as a Conservative candidate in Lac-Saint-Louis in the next federal election.[4] When asked in a television interview why he accepted the appointment while intending to run for a Commons seat, Smith complained that he was taking a "dramatic, catastrophic" pay cut by serving as a senator,[5] a remark for which Smith has been criticized.[6]

Smith was defeated in his attempt to enter Parliament, placing third behind the incumbent Liberal MP and the NDP candidate, and it was announced on May 18, 2011, he would be re-appointed to the Senate.

The Conservative Senate Caucus elected Smith its leader on March 28, 2017; Smith defeated Senators Linda Frum and Stephen Greene for the position, and took office on April 1, 2017.[7]